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Biomedical subjects

K Matsubara

Publications and source records attributed to K Matsubara.

At least 379 records · Page 21Linked to original sources
PubMed1989

Expression and replication of hepatitis B virus genome in transgenic mice.

We produced transgenic mice by microinjecting a partial tandem duplication of the complete hepatitis B virus (HBV) genome into fertilized eggs of C57BL/6 mice. One of eight transgenic mice was a high producer for HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) in the serum. The HBV genomes were transmitted to the next generation and these F1 mice also produced HBsAg and HBeAg. mRNAs of 3.5, 2.1, and 0.8 kilobases were detected in the livers and the kidneys of these mice. In addition, a 0.8-kilobase RNA was detected in the testis. Single-stranded and partially double-stranded HBV DNAs were shown to be produced in the cytoplasm of the liver and kidneys. These HBV DNAs were associated with the core particles, indistinguishable from nucleocapsid produced in an infected human liver. Viral genome DNA was detected in the serum. These results demonstrate that the HBV genome integrated into the mouse chromosome acted as a template for viral gene expression, allowing viral replication. Thus, these transgenic mice should be useful for detailed studies of the replication and expression of HBV and for pathological studies of hepatitis, including the development of hepatocellular carcinoma.

Animals↗
PubMed1989

An in vitro system for infection with hepatitis B virus that uses primary human fetal hepatocytes.

An in vitro culture of human fetal hepatocytes has been employed for infection by hepatitis B virus (HBV) virions that are produced by an established human hepatoma cell line, HB 611. HBV surface antigen and e antigen were released into the medium 3-4 days after infection, and production continued thereafter. RNA synthesis with similar kinetics was observed. Viral DNA replication started 2 days after infection, and replicative HBV DNA that included relaxed circles, single-stranded minus strands, and closed circles accumulated during 16 days of incubation. Immunofluorescent study using fluorescein isothiocyanate-labeled rabbit antisera directed against HBV core antigen revealed that this antigen is present in the nuclei in 12% of the infected cells. Particles containing HBV DNA were detected in the culture medium and were infectious. Thus, this in vitro infection system closely mimics infection in vivo and it allows detailed studies on early events associated with human HBV entry into cells and subsequent replication and integration.

Carcinoma, Hepatocellular↗
PubMed1989

Actions of three human alpha-amylases expressed in yeast on modified substrates and the amino acid residues causing their different actions.

The mode of action of an alpha-amylase (yHXA) which was the gene product of a newly found human alpha-amylase gene expressed in yeast on synthetic substrates was compared with those of the gene products (yHSA and yHPA) of human salivary and pancreatic alpha-amylase gene in yeast. The substrates used were phenyl alpha-maltopentaoside (G5 phi) and its derivatives in which the CH2OH groups of the non-reducing-end glucose residues were converted to CH2NH2 (AG5 phi), COOH (CG5 phi), or CH2I (IG5 phi). The digests were subjected to HPLC to determine the amounts of products. The HPLC analysis revealed that yHXA and yHSA bound G5 phi to their active sites in similar manners to give the same products, while yHPA hydrolyzed it in a different way. Modifications of the non-reducing-end glucose of G5 phi caused change of the binding mode to the active sites of the enzymes. AG5 phi and CG5 phi were hydrolyzed by the enzymes to give more phenyl alpha-glucoside (G phi) and less phenyl alpha-maltoside (G2 phi), while IG5 phi gave more G2 phi and less G phi, compared with G5 phi. The substrate binding mode of yHXA changed more extensively than that of yHSA. The results suggested that there exists an amino acid replacement between yHXA and yHSA. The amino acid residues replaced are neither acidic nor basic, are located in subsite S3, and interact with the CH2OH residue of the non-reducing-end glucose residue of G5 phi.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1989

Immolation after drinking kerosene.

An unusual suicide is described in which analysis of circulating kerosene components at autopsy suggested that the victim had drunk kerosene and then had poured it over his body, ignited it, and burned to death.

Burns↗
PubMed1989

Demethylation by 5-azacytidine results in the expression of hepatitis B virus surface antigen in transgenic mice.

In 14p3HB transgenic mice, which carry three tandem copies of hepatitis B virus (HBV) DNA, the HBV DNA was significantly methylated and no viral proteins were produced. To analyze the causal relationship between hypermethylation and gene inactivity, 5-azacytidine was injected into the mice to demethylate HBV DNA. When postnatal 14p3HB mice were treated with the drug, hepatitis virus surface antigen was produced in these mice by 3 weeks of age, and the integrated HBV DNA of the liver was less heavily methylated. Our results suggest that injection of 5-azacytidine can be used to efficiently activate a silent transgene such as HBV DNA in transgenic mice.

Animals↗
PubMed1989

Sustained release of buserelin acetate, a luteinizing hormone-releasing hormone agonist, from an injectable oily preparation utilizing ethylated beta-cyclodextrin.

The possible use of heptakis (2,6-di-O-ethyl)-beta-cyclodextrin (DE-beta-CyD) as a parenteral sustained-release carrier for buserelin acetate, a luteinizing hormone-releasing hormone superagonist, has been examined. The in-vitro release of buserelin from the oily suspension was significantly retarded by the complexation with DE-beta-CyD, mainly due to the poor water solubility of the complex. A single subcutaneous injection of the suspension containing the buserelin-DE-beta-CyD complex to rats provided an effective continuous plasma level of buserelin lasting for at least one month, indicating a potential therapeutic efficacy for the treatment of the endocrine-dependent diseases. These results suggest that DE-beta-CyD serves as an injectable sustained-release drug carrier suitable for chronic treatment with buserelin acetate.

Animals↗
PubMed1989

Assignment of human pepsinogen C (PGC) gene to chromosome 6.

cDNA of rat pepsinogen C (PGC) hybridizes to, among others, a 3.2-kb band in Southern blot analysis of BamHI-cleaved human genomic DNA. This property was employed to localize the human PGC gene. Use of flow-sorted human chromosomes and 12 human x mouse somatic cell hybrid lines demonstrated that the gene is located on chromosome 6.

Animals↗
PubMed1989

[Sequential changes in blood pressure and electrocardiographic findings over seventeen years in three different regions in Okayama Prefecture].

The sequential changes in blood pressure and electrocardiographic findings of populations living in three districts of Okayama prefecture, with differing environments and life styles, were analyzed during the seventeen year period from 1966 to 1982. Furthermore, factors influencing the causes of mortality among these populations were evaluated in 790 males and 1, 118 females (total 1,908), aged from 35 to 65 years at the beginning of the survey (1966). During the survey period 94 subjects moved out of the district and 210 subjects died, so that in 1982, 975 subjects (61.1%) could be examined. Cerebrovascular disease, cancer, and cardiac disease were the major causes of death in all these districts. A higher mortality from cerebrovascular disease was recorded in the mountainous district, with harsh weather and living conditions, in contrast to the other two lowland district. There was no significant difference in mortality due to cardiac disease among the three districts. In the mountainous district, the incidence of hypertension, especially systolic hypertension, was higher than in the other two districts throughout the whole of this survey. However, after 1980, the difference in the incidence of hypertension among the districts diminished sequentially. The incidence of hypertension was higher in the elderly than in younger subjects. However, even this age difference in incidence was seen to diminish sequentially, (especially for diastolic hypertension). The ratio of the number of people who were actually treated to the population who needed hypertensive therapy increased gradually, and in 1978 there was no significant difference concerning this ratio among the three districts. Finally over 80% of the subjects who qualified for antihypertensive therapy were treated continuously. The appearance ratio of abnormal ECG findings, (Minnesota Code, Code 3, Code 3 + 4, 5 and especially Code 4 and 5), increased in proportion to the increase of blood pressure in the hypertensive group. The sequential appearance ratios for the borderline hypertension and stage I hypertension groups showed an inverse relationship to that of the normal group. However the appearance ratios of stage II & III hypertension groups increased sequentially with no relation to that of the normal group. Subjects whose ECG showed ST-T changes without subjective symptoms apparently increased sequentially in all districts. The incidence ratios of angina pectoris and myocardial infarction showed no significant sequential changes. These results suggested that high blood pressure (both systolic and diastolic) was controlled fairly well in all age groups by therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Exercise body surface mapping in patients with left ventricular hypertrophy: comparison with stress thallium scans (SPECT).

To evaluate exercise-induced myocardial ischemia in patients with electrocardiographic evidence of left ventricular hypertrophy (LVH), including ST.T changes, body surface maps (QRST area maps) were recorded using 87 lead points before and after exercise. The patterns of the subtraction QRST area maps (S-maps) were compared with the findings of stress thallium (T1) scans in 31 patients with hypertrophic cardiomyopathy and in five with essential hypertension. All 18 patients whose S-maps revealed changes less than -40 muVS or only an increase over the anterior chest region showed no positive findings on the stress T1 scans. However, there were clearly positive findings on stress T1 scans in eight (89%) of nine patients whose S-maps revealed changes greater than -40 muVS over a wide precordial region or in six (67%) of nine patients whose S-maps revealed increases over the anterior chest region and had accompanying changes greater than -40 muVS somewhere over the precordial region. These results suggested that exercise QRST area maps could differentiate exercise-induced myocardial ischemia from LVH with ST.T changes.

Aged↗
PubMed1989

[Molecular aspects of human hepatocellular carcinoma].

It is now evident that development of hepatocellular carcinoma (HCC) in human is associated with a long series of cellular and tissue changes that precede the ultimate development of the cancer. During recent years, enormous progress in molecular research on HCC has been made, particularly in the area of integration of HBV DNA to host cell and oncogene association with carcinogenicity. A high ratio of HCCs from patients in endemic area has integrated HBV DNA in cellular DNA and in some cases, chromosomal translocations associated with HBV integration were observed, suggesting that the integration or the results thereof are connected with cancer development. Employing a DNA-mediated transfection assay using NIH3T3 mouse fibroblasts with high molecular weight DNA, we detected three cellular transforming genes (lca, N-ras, hst) in primary human HCC. However, little is known as to the linkage between the activation of these genes and liver carcinogenesis. In most human primary HCC tissues, at least two oncogenes, c-myc and N-ras are overexpressed, while in some cases other oncogenes c-fos or lca are overexpressed. It is likely that multiple c-oncogens are important in HCC, but specific transcripts for the malignancy of HCC were not detected. At present, we could not find any relationship between the expression of c-oncogenes and integration of HBV, serological markers or the degree of differentiation. Of the experimental animals most frequently used for studies of liver cancer, the rat is best understood and mimics closely many of the lesions in humans. It is of interest to consider that the identification and elucidation of the mechanisms underlying carcinogenic processes in the rat may offer testable hypotheses for steps in the human.

Adult↗
PubMed1989

[Hepatitis B virus: DNA integration and hepatocellular carcinoma].

Hepatitis B Virus DNA integrates into host cell DNA upon infection. Analyses of early integrants have revealed that the origin of DNA synthesis in the viral genome plays a major role in the integration process. In liver cancers many of the integrants are found in different structures, suggesting that the primary integrants must have undergone secondary rearrangements. Such rearrangements include large deletions, translocations, inversions, and local amplifications. The mechanism that leads to these rearrangements are inferred, and their role in development of hepatocellular carcinomas is discussed.

Animals↗
PubMed1989

[Computerized digital image analysis of optic nerve heads with a three-dimensional image analyzer, IMAGEnet and a comparison with the Optic Nerve Head Analyzer].

Computerized digital image analysis of the optic nerve heads of 17 eyes with various sizes of optic disc cupping was performed using two kinds of three dimensional image analyzers, the IMAGEnet and the Optic Nerve Head Analyzer (ONHA). Intraphotographic error variances of measurements with both instruments were evaluated by measuring each image of the optic discs twice. The mean coefficient of variation (CV) with the IMAGEnet for the vertical cup/disc ratio, the horizontal cup/disc ratio, the cup volume, the rim area, and the rim area/disc area ratio were 3.75%, 3.03%, 7.89%, 2.55% and 1.36%, respectively. With the ONHA, the mean CV for the total cup/disc ratio, the cup volume, the rim area, and the rim area/disc area ratio were 0.82%, 0.21%, 2.39%, and 1.56%, respectively. The value of the cup/disc ratio and the cup volume obtained by the IMAGEnet was smaller than those by the ONHA (p greater than 0.1). Conversely, the rim area and rim area/disc area ratio measured by the IMAGEnet were statistically significantly larger than those by the ONHA (p = 0.01). Statistically significantly positive correlation was demonstrated for measurements made by both instruments in all disc parameters (p less than 0.01). These results seem to indicate the high reliability of the two instruments, however, further investigation is needed for the evaluation of the accuracy of measurements.

Glaucoma↗
PubMed1989

[Two brothers with reflux nephropathy].

This paper reports two brothers with reflux nephropathy. Patients who were 10-year-old and 12-year-old were referred to our hospital due to proteinuria and deterioration of renal function. Diagnosis of reflux nephropathy was made on drip infusion pyelography (DIP), voiding cystogram (VCG), and renal biopsy findings. The following findings were observed in renal tissues; focal and segmental sclerosis by light microscopy, IgM deposition by immunofluorescent microscopy, and glomerular basement membrane alterations and detachment of podocytes by electron microscopy. The HLA typing and analysis showed that both brothers and their mother possessed HLA-A9, which is reported to be closely associated with progression of primary reflux nephropathy to end-stage renal disease.

Child↗
PubMed1989

[Intraventricular flow dynamics in hypertrophic cardiomyopathy with midventricular obstruction investigated by Doppler echocardiography].

Seven patients with hypertrophic cardiomyopathy having midventricular obstruction (MVO) were examined using two-dimensional, conventional Doppler and color Doppler echocardiography to investigate intraventricular flow conditions. The controls were 35 patients with hypertrophic cardiomyopathy without MVO. All MVO patients had "hour-glass" LV cavities during systole, resulting from either hypertrophy at the midventricular level or hypertrophied papillary muscles, where systolic mosaic signals originated. Systolic peak flow velocities at the midventricle ranged from 2.5 to 4.2 m/s, proving the presence of a pressure gradient between the apex and the base of the LV. In fact, a pressure drop of 15-30 mmHg was demonstrated in four patients who underwent cardiac catheterization. These high velocity jet flows were not detectable at the midventricle in the control subjects. Peak ejection velocities in the outflow tracts were significantly lower in patients with MVO compared to those with hypertrophic cardiomyopathy and subaortic stenosis (129 +/- 29 vs 384 +/- 111 cm/s; p less than 0.001). As midventricular obliteration became severe, systolic jets at the midventricle increased in velocity. Waveforms changed from single- to double-peaked, and lasted until the isovolumic relaxation or the rapid filling phase beyond the second heart sound. Consequently, isovolumic relaxation waveforms at the midventricle using the apical approach changed the direction; from "the base to apex" to "the apex to base". An isovolumic signal away from the transducer was only observed in two patients without MVO. Diastolic color reversal and mosaic signals at the midventricle were also seen in five of the seven patients with MVO. Peak flow velocities in the rapid filling phase were significantly higher at the papillary muscle level than at the mitral valve level, indicating that MVO continues up to early diastole. It was suggested that MVO disturbs intraventricular flow dynamics during both systole and diastole. Color Doppler echocardiography is particularly useful in determining the site of obstruction and allows further evaluation by pulsed and continuous wave Doppler techniques to precisely measure pressure gradients. With routine, careful use of Doppler echocardiography, MVO may prove to be a more common entity than was previously believed.

Adult↗
PubMed1988

The structure of the human thyrotropin beta-subunit gene.

We have determined and characterized the entire structure of the human thyrotropin beta-subunit (TSH beta) gene. It is 4.5 kb in size and separated into three exons. Primer extension analysis showed one transcription start point, and S1 mapping analysis showed two blocks of polyadenylation sites in normal pituitaries. The same transcripts were observed in TSH-producing adenomas. The 5'-flanking region contains two 'TATA' boxes, two 'CAAT' boxes, and two sequences similar to the cyclic AMP-responsive elements.

Amino Acid Sequence↗
PubMed1988

Identification of two novel members of erbA superfamily by molecular cloning: the gene products of the two are highly related to each other.

Two v-erbA-related genes, named ear-2 and ear-3, have been identified in the human genome and characterized by cDNA cloning. These genes are predicted to encode proteins that are very similar in primary structure to receptors for steroid hormones or thyroid hormone (T3). In addition, amino acid sequences of the ear-2 and ear-3 gene products are very similar each other especially at the DNA binding domain (86% homology) and at the putative ligand binding domain (76% homology). Northern hybridization with ear DNA probes of RNAs from various tissues of a human fetus reveals that the expression of ear-2 is high in the liver whereas the expression of ear-3 is relatively ubiquitous. Hybridization analysis of DNAs from sorted chromosomes shows that the ear-2 gene is located on chromosome 19 and ear-3 on chromosome 5, indicating that the two genes are clearly different from each other.

Alpharetrovirus↗